BS/EN 303-6-2019 pdf download.Heating boilers Part 6: Heating boilers with forced draught burners — Specific requirements for the domestic hot water operation and energy performance of water heaters and combination boilers with atomizing oil burners of nominal heat input not exceeding 70 kW.
— central heating water (if necessary): see standards about boilers (flow 80 °C — return 60 °C).
For the tests:
— the domestic water pressure is the difference between the static inlet and outlet pressures of the boiler measured as close as possible to the boiler;
— the inlet and outlet temperatures of the domestic water are measured in the centre of the flow and as close as possible to the boiler.
in certain tests, a low inertia thermometer is used.
6.1.2 AdJustment of the domestic water pressure
The domestic water pressure shall be adjusted to the required value within a tolerance of ±4 %.
6.1.3 OperatIon of the boiler
Except where otherwise specified, the tests are carried out with the boiler operating in the domestic
water mode and the summer operating mode.
6.2 Safety of the domestic hot water circuit
6.2.1 Instantaneous and storage types
6.2.1.1 Soundness of the parts containing domestic water
The domestic water circuit is subjected to a pressure of 1.5 times the maximum pressure given on the data plate for 10 mm.
it is checked that the requirements of 5.2.1.1 are met.
6.2.1.2 Overheating of the domestic hot water by the central heating circuit
The central heating circuit thermostat is set at its maximum position.
The appliance operates continuously for one hour at the nominal heat input in the central heating mode, without drawing domestic hot water. A draw off at the specific rate D is then carried out and the requirement of 5.2.1.2 is checked.
6.2.1.3 Failure of the domestic hot water temperature control device
To check the requirements of 5.2.1.3, the draw off domestic water rate Is progressively reduced after having put out of action the adjusting control of the domestic water circuit, in accordance with the test methods relating to the limit thermostat or the temperature limiter with the boiler operating at its maximum heat input.
The boiler is operated at the nominal domestic hot water heat input with a domestic water supply pressure of 2 bar.
Starting with this 2 bar supply pressure, the pressure is progressively reduced until the burner is extinguished. The water outlet temperature is measured continuously with a low inertia thermometer. The maximum temperature is measured and shall satisfy the requirements of 5.2.2.1.
6.2.2.2 OverheatIng of the domestic hot water
The boiler is operated at the nominal domestic hot water heat input, where appropriate. The water rate and any water temperature control are adjusted to obtain the maximum water temperature at the nominal domestic hot water heat Input.
After the boiler has operated for 10 mm, the hot water delivery tap is turned off quickly. After lOs the tap is turned on quickly and the highest temperature at the centre of the flow, as close as possible to the boiler outlet, is measured by means of a low inertia thermometer. The boiler remains in operation until it has again reached its steady-state condition. The same measurements are made during similar operating cycles, but with the time that the draw off Is stopped increased each time by 10 s. until the maximum temperature is obtained.
It is checked that the requirement of 52.2.2 is met.
6.2.3 Storage type
6.2.3.1 Maximum temperature of the domestic hot water
The boiler is operated at the nominal domestic hot water heat input with the domestic water thermostat at its maximum position. A draw off is carried out after a shut-down of the burner. The maximum temperature measured shall meet the requirement of 5.2.3.1.
6.2.3.2 Overheating of the domestic hot water
The test starts after the tank or the thermal store has reached temperature and after the burner has been shut down a second time by the controls. Water is drawn off several times at a rate corresponding to 5 % of the water capacity of the tank, in litres per minute.
On each occasion, water is drawn until the burner ignites and at least 95 % of the nominal domestic hot water heat input is obtained. The next draw off then takes place immediately after the burner shuts down, and so on until the maximum temperature is obtained.
For modulating burners or multi-stage burners, the following draw off takes place when the fuel rate has decreased at least to 50 % of the maximum domestic hot water heat input reached.
At the start of each draw off, the temperature of the delivered water is measured and it is checked that the requirement of 5.2.3.2 is met.BS/EN 303-6-2019 pdf download.